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S Morita

Publications and source records attributed to S Morita.

At least 55 records · Page 3Linked to original sources
PubMed2001

The SOCS box of SOCS-1 accelerates ubiquitin-dependent proteolysis of TEL-JAK2.

Fusion of the TEL gene on 12p13 to the JAK2 tyrosine kinase gene on 9p24 has been found in human leukemia. TEL-mediated oligomerization of JAK2 results in constitutive activation of the tyrosine kinase (JH1) domain and confers cytokine-independent proliferation on interleukin-3-dependent Ba/F3 cells. Forced expression of the JAK inhibitor gene SOCS1/JAB/SSI-1 induced apoptosis of TEL-JAK2-transformed Ba/F3 cells. This suppression of TEL-JAK2 activity was dependent on SOCS box-mediated proteasomal degradation of TEL-JAK2 rather than on kinase inhibition. Degradation of JAK2 depended on its phosphorylation and its high affinity binding with SOCS1 through the kinase inhibitory region and the SH2 domain. It has been demonstrated that von Hippel-Lindau disease (VHL) tumor-suppressor gene product possesses the SOCS box that forms a complex with Elongin B and C and Cullin-2, and it functions as a ubiquitin ligase. The SOCS box of SOCS1/JAB has also been shown to interact with Elongins; however, ubiquitin ligase activity has not been demonstrated. We found that the SOCS box interacted with Cullin-2 and promoted ubiquitination of TEL-JAK2. Furthermore, overexpression of dominant negative Cullin-2 suppressed SOCS1-dependent TEL-JAK2 degradation. Our study demonstrates the substrate-specific E3 ubiquitin-ligase-like activity of SOCS1 for activated JAK2 and may provide a novel strategy for the suppression of oncogenic tyrosine kinases.

Animals↗
PubMed2001

Effect of phosphodiesterase III inhibitor on contractility, afterload, and vascular capacitance during right heart bypass preparation.

OBJECTIVES: Phosphodiesterase III inhibitors, which have both positive inotropic and vasodilatory effects, occasionally cause hypotension due to afterload reduction and possibly due to preload reduction caused by the increase in vascular capacitance. METHODS: Six open-chest adult mongrel dogs were used to compare the effects on left ventricular contractility, afterload, and vascular capacitance of the phosphodiesterase III inhibitor, olprinone, with those of dobutamine using a right-heart-bypass model. Contractility and afterload were evaluated by the left ventricular pressure-volume relations with the use of a conductance catheter to derive the end-systolic elastance (Ees) and the effective arterial elastance (Ea). Vascular capacitance change was evaluated by reservoir volume change under a constant bypass flow (80 ml/kg per minute). RESULTS: Ees increased significantly both with dobutamine (7.6 +/- 2.8 to 14.3 +/- 4.8 mmHg/ml, p < 0.05) and with olprinone (7.6 +/- 2.9 to 11.5 +/- 4.2 mmHg/ml, p < 0.05). Ea did not change with dobutamine (14.4 +/- 3.5 to 14.5 +/- 3.6 mmHg/ml, p = 0.9), whereas it decreased with olprinone (14.0 +/- 4.1 to 11.4 +/- 3.8 mmHg/ml, p = 0.093). Reservoir volume increased after the infusion of dobutamine (-94.0 +/- 39.8 ml), and decreased after the infusion of olprinone (-114.0 +/- 62.3 ml). The difference was statistically significant (p = 0.007). The reservoir volume change indicated that vascular capacitance decreased with dobutamine, and increased with olprinone. CONCLUSIONS: Pre- and afterload reduction of olprinone combined with the positive inotropic effect are useful in treating congestive heart failure and managing low cardiac output syndrome after cardiac surgery.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2001

Early and late results of total correction of congenital cardiac anomalies in infancy.

OBJECTIVE: We evaluated long-term results of surgical correction of congenital cardiac anomalies in infancy. METHODS: We reviewed cases of 856 patients who underwent complete correction of major cardiac anomalies in the first year of life during last 24 years at our institution, and analyzed results. Surgery involved ventricular septal defect (n = 453), tetralogy of Fallot (n = 92), atrioventricular canal defect (n = 93), and complete transposition of the great arteries (n = 218). RESULTS: Operative mortality was 2.2% in ventricular septal defect, 0% in tetralogy of Fallot, 8.6% in atrioventricular canal defect, and 4.1% in complete transposition of the great arteries. Freedom from reoperation at 20 years was 96.5 +/- 2.0% and actuarial survival was 94.2 +/- 1.3% in ventricular septal defect. Freedom from reoperation at 15 years was 90.5 +/- 3.9% in tetralogy of Fallot and 86.6 +/- 4.4% in atrioventricular canal defect. Actuarial survival at 15 years was 97.8 +/- 1.6% in tetralogy of Fallot, 85.7 +/- 3.7% in atrioventricular canal defect, and 89.9 +/- 2.2% in complete transposition of the great arteries. Actuarial survival in complete transposition of the great arteries was significantly better in arterial than in atrial switch operations. CONCLUSIONS: Total correction of ventricular septal defect, tetralogy of Fallot, atrioventricular canal defect, and complete transposition of the great arteries in infancy was conducted safely, but the incidence of reoperation in late follow-up must be reduced.

Endocardial Cushion Defects↗
PubMed2001

Hepatobiliary cystadenoma combined with multiple liver cysts: report of a case.

Hepatobiliary cystadenomas are rare benign tumors with malignant potential. They are almost always solitary lesions accompanied by multilocular cysts in the liver, and are difficult to differentiate from cystadenocarcinoma, despite the diagnostic modalities available. This report describes a case of hepatobiliary cystadenoma with multiple cysts in the left hepatic lobe, diagnosed by magnetic resonance imaging in a 48-year-old woman. Abdominal computed tomography revealed only multiple cystic lesions in the left lobe, but cholangiography via a nasogastric biliary drainage tube combined with percutaneous transhepatic cholangiography showed a stenotic region with fine irregularity in the left lateral posterior segmental bile duct and left lateral anterior segmental bile duct. Hepatobiliary cystadenocarcinoma with multiple liver cysts was suspected. We performed left hepatectomy, and microscopic examination confirmed a diagnosis of hepatic cystadenoma with multiple liver cysts. There was no nuclear atypia or mitosis in the epithelium of the locus, which was constructed of simple columnar-to-cuboidal epithelium with basal nuclei. The patient is well without recurrence more than 4 years after surgery.

Bile Duct Neoplasms↗
PubMed2001

Atherosclerotic aneurysm in the circumflex retroesophageal right aortic arch.

A 63-year-old man had a distal arch aneurysm combined with a circumflex retroesophageal right aortic arch, which is a rare form of vascular ring. By using combined median sternotomy and left thoracotomy under deep hypothermia and retrograde cerebral perfusion, total arch replacement with a vascular graft was successful. We describe our surgical strategy for arch aneurysm associated with an uncommon congenital vascular malformation.

Aorta, Thoracic↗
PubMed2001

Impacts of pulsatile systemic circulation on endothelium-derived nitric oxide release in anesthetized dogs.

BACKGROUND: The effects of pulsatile flow on endothelium-derived nitric oxide-mediated vasodilation are not fully elucidated in an in vivo model. METHODS: A left ventricular assist device was established in 10 anesthetized dogs with a centrifugal pump and an air-driven pneumatic pump. The systemic circulation was subjected to step changes in the frequency of pulse (0, 30, 60, and 120 bpm with a fixed pulse pressure of 50 mm Hg), and in the amplitude of pulse (0, 20, and 50 mm Hg with a fixed pulse rate of 120 bpm). Hemodynamic variables and calculated total systemic vascular resistance were compared before and after the administration of N(G)-Nitro-L-arginine Methyl Ester (L-NAME) (20 mg/kg). Plasma NO2-/NO3- concentration levels were also measured. RESULTS: Total systemic vascular resistance significantly decreased while plasma NO2-/No3- concentration increased in response to the rise in both pulse rate and pulse pressure. However, L-NAME significantly diminished these effects of pulsatile flow. CONCLUSIONS: Both the frequency and the amplitude of pulse wave in the systemic circulation are significant independent stimuli for endothelium-derived nitric oxide-mediated vasodilation in vivo.

Animals↗
PubMed2001

Intraocular lens implantation in a child with monocular cataract and anterior persistent hyperplastic primary vitreous.

A 3-year-old girl had phacoemulsification during which the presence of anterior persistent hyperplastic primary vitreous (PHPV) was discovered. Visual rehabilitation comprised contact lens use for 1 year. However, visual acuity deteriorated gradually because of secondary cataract formation. In a second surgery 1 year after the first, the posterior capsule was incised, followed by an anterior vitrectomy and intraocular lens implantation. At the last follow-up 6 months after the second surgery, there was no evidence of ocular complications and best corrected visual acuity was 0.6.

Cataract↗
PubMed2001

Prediction of difficult airway in school-aged patients with microtia.

BACKGROUND: Because the ear and mandible develop from the first and second branchial arches and first branchial cleft, abnormalities of the ear may be a sign that intubation will be difficult. We hypothesized that children with microtia would have a greater incidence of difficult laryngeal visualization with conventional rigid laryngoscopy compared to those with normal facial anatomy. METHODS: We enrolled 93 consecutive school-aged patients with microtia undergoing the first stage of total reconstruction of the auricle. Age-matched patients with normal facial anatomy served as controls. Each patient was examined for the presence or absence of the five dysmorphic features of hemifacial microsomia: orbital asymmetry, mandibular hypoplasia, ear deformity, nerve involvement, soft tissue deficiency (OMENS classification). After a standardized induction of anaesthesia, the laryngeal view during rigid laryngoscopy was graded. RESULTS: The incidence of difficult laryngeal view was 42% in the patients with bilateral microtia, 2% in those with unilateral microtia and 0% in the controls. CONCLUSIONS: There was a strong positive correlation between the number of involved abnormal anatomical components according to the OMENS classification and the degree of difficult visualization of the larynx in patients with both bilateral and unilateral microtia (Spearman rank order correlation coefficient=0.85 and 0.88, respectively).

Adolescent↗
PubMed2001

Orally given melatonin may serve as a probe drug for cytochrome P450 1A2 activity in vivo: a pilot study.

BACKGROUND: Melatonin is a hormone that is metabolized by cytochrome P450 (CYP) 1A2 to its main primary metabolite 6-hydroxymelatonin. We therefore evaluated the utility of oral melatonin as a marker of hepatic CYP1A2 activity. METHODS: Twenty-five milligrams of melatonin was given at 9:30 am to 12 healthy Swedish volunteers, who had previously been phenotyped for CYP1A2 with caffeine. Melatonin and conjugated 6-hydroxymelatonin were analyzed by liquid chromatography-mass spectrometry in blood samples taken between 0.5 and 6.5 hours after drug intake. Serum concentrations of melatonin and conjugated 6-hydroxymelatonin, or their ratio at different time points, and the apparent melatonin clearance were tested for correlation with caffeine clearance. RESULTS: We found a significant correlation between apparent clearance of melatonin and caffeine clearance with a Spearman rank correlation coefficient (Rs) of 0.75 (P =.005). The melatonin concentration 1.5 hours after administration also closely correlated with the caffeine clearance (Rs = -0.62; P =.03). Inclusion of conjugated 6-hydroxymelatonin gave no closer correlations. CONCLUSION: Melatonin might be developed as an alternative to caffeine as a probe drug for CYP1A2 phenotyping.

Administration, Oral↗
PubMed2001

Tissue-engineered vascular autograft: inferior vena cava replacement in a dog model.

Tissue-engineered vascular autografts (TEVAs) were made by seeding 4-6 x 10(6) of mixed cells obtained from femoral veins of mongrel dogs onto tube-shaped biodegradable polymer scaffolds composed of a polyglycolid acid (PGA) nonwoven fabric sheet and a copolymer of L-lactide and caprolactone (n = 4). After 7 days, the inferior vena cavas (IVCs) of the same dogs were replaced with TEVAs. After 3, 4, 5, and 6 months, angiographies were performed, and the dogs were sacrificed. The implanted TEVAs were examined both grossly and immunohistologically. The implanted TEVAs showed no evidence of stenosis or dilatation. No thrombus was found inside the TEVAs, even without any anticoagulation therapy. Remnants of the polymer scaffolds were not observed in all specimens, and the overall gross appearance similar to that of native IVCs. Immunohistological staining revealed the presence of factor VIII positive nucleated cells at the luminal surface of the TEVAs. In addition, lesions were observed where alpha-smooth muscle actin and desmin positive cells existed. Implanted TEVAs contained a sufficient amount of extracellular matrix, and showed neither occlusion nor aneurysmal formation. In addition, endothelial cells were found to line the luminal surface of each TEVA. These results strongly suggest that "ideal" venous grafts with antithrombogenicity can be produced.

Animals↗
PubMed2001

Identification of a new imprinted gene, Rian, on mouse chromosome 12 by fluorescent differential display screening.

Systematic screening of differentially expressed genes among androgenetic, parthenogenetic, and normal embryos by means of fluorescent differential display revealed five imprinted genes. One of them, named Rian, was expressed exclusively from the maternal allele and was closely linked to an imprinted gene, Meg3(Gtl2), mapped to the distal end of chromosome 12. The Rian transcript did not have any apparent open reading frame, and its transcript was exclusively localized to the nucleus.

Animals↗
PubMed2001

Minimum alveolar concentration (MAC) of xenon with sevoflurane in humans.

BACKGROUND: Although more than 30 yr ago the minimum alveolar concentration (MAC) of xenon was determined to be 71%, that previous study had technological limitations, and no other studies have confirmed the MAC value of xenon since. The current study was designed to confirm the MAC value of xenon in adult surgical patients using more modern techniques. METHODS: Sixty patients were anesthetized with sevoflurane with or without xenon. They were randomly allocated to one of four groups; patients in group 1 received no xenon, whereas those in groups 2, 3, and 4 received end-tidal concentrations of 20, 40, and 60%, respectively (n = 15 each group). Target end-tidal sevoflurane concentrations were chosen using the "up-and-down" method in each group. After steady state sevoflurane and xenon concentrations were maintained for at least 15 min, each patient was monitored for a somatic response at surgical incision. Somatic response was defined as any purposeful bodily movement. The MAC of sevoflurane and its reduction by xenon was evaluated using the multiple independent variable logistic regression model. RESULTS: The interaction coefficient of the multiple variable logistic regression was not significantly different from zero (P = 0.143). The MAC of xenon calculated as xenon concentration that would reduce MAC of sevoflurane to 0% was 63.1%. CONCLUSIONS: The authors could not determine whether interaction in blocking somatic responses in 50% of patients is additive. The MAC of xenon is in the range of the values that were predicted in a previous study.

Adult↗
PubMed2001

The midlatency auditory evoked potentials predict responsiveness to verbal commands in patients emerging from anesthesia with xenon, isoflurane, and sevoflurane but not with nitrous oxide.

BACKGROUND: It has recently been demonstrated that the approximately 40-Hz spectral power of the midlatency auditory evoked potential (MLAEP) correlates well with wakefulness during desflurane or propofol anesthesia. The aim of this study was to characterize how other inhalational anesthetics affects the MLAEP as the patients regain responsiveness to simple verbal command during emergence from anesthesia. METHODS: Sixty patients were randomly assigned to receive xenon, isoflurane, sevoflurane, or nitrous oxide (N2O) supplemented with epidural anesthesia. During emergence, the concentration of an anesthetic was decreased in 0.1-minimum alveolar concentration (MAC) decrements from 0.8 MAC or from 70% in the case of N2O, and each new concentration was maintained for 15 min. Every 5 min during each equilibration period, the MLAEP was recorded and the patients were asked to open their eyes and squeeze and release the investigator's hand. This process was repeated until the first response to either of these commands was observed. RESULTS: Thirteen patients were excluded because of technical reasons. The preanesthetic MLAEP showed a periodic waveform, where the Na-Pa-Nb complex was the most prominent component contributing to the high energy around 29-39 Hz in the power spectrum. Emergence from xenon, isoflurane, and sevoflurane anesthesia produced similar changes in the MLAEP. The spectral power for the frequency 29 Hz or greater was severely suppressed at 0.8 MAC but significantly recovered between the concentration only 0.1 MAC higher that permitting the first response to command and that associated with the first response. In contrast, N2O hardly affected the MLAEPs, even at the concentrations producing unresponsiveness. Two patients did not lose responsiveness even at the highest concentration tested (70%). CONCLUSIONS: The MLAEP is closely associated with responsiveness to verbal command during emergence from anesthesia with xenon, isoflurane, and sevoflurane but not with N2O.

Adult↗